Various types of machines have been proposed for converting a shallow cup into a drawn and ironed container. Machines of this type usually consist of a punch or ram that is reciprocated along a path on a frame with a plurality of ironing dies arranged along the path. The ironing dies cooperate with the punch to reduce the wall thickness of the shallow cup and increase the height thereof.
One type of machine that has been used for this purpose is disclosed in U.S. Pat. No. 3,735,629. The apparatus disclosed in this patent consists of a redraw assembly, three ironing assemblies and a stripper assembly all arranged along the path for a punch so that a cup can be placed on the end of the punch and then forced through the respective assemblies to decrease the wall thickness and increase the height. At the end of the stroke for the punch, a domer assembly cooperates with the end of the punch to reform the end wall and the finished container is removed from the punch by the stripper assembly while the punch is returned to its original position.
For effective and prolonged operating life, it is essential that proper alignment of the dies and the ram be established and maintained. Various proposals have been suggested for mounting the dies and one type is disclosed in the above-mentioned patent. Each ironing die and the redraw die are mounted in separate cartridges and the respective cartridges are then mounted on the frame of the unit along the axis of movement of the ram or punch. While cartridge-type tool packs are known, some difficulties have been encountered in maintaining accurate alignment between the respective assemblies during installation and subsequent operation.
Another problem encountered during a drawing and ironing operation is the large amount of frictional heat that is developed in the ironing dies as well as the punch and each of the cups being ironed. In order to dissipate this heat, it is customary to supply a lubricant-coolant adjacent each of the ironing dies to transfer the heat from the ironing dies and the periphery of the cup being ironed to the lubricant-coolant. The lubricant-coolant is usually a highly diluted mixture, such as 95% water and 5% synthetic or water soluble lubricant. One type of lubricating means is disclosed in the above-mentioned patent wherein a lubricant ring is located adjacent each of the ironing rings and a large volume of lubricant is supplied thereto and flows out the bottom adjacent each ironing ring.
In a tool pack assembly where all the components are enclosed in a housing, the large volume of lubricant must flow through the open end of the stripper assembly and has a tendency to fill the drawn and ironed container after the punch is withdrawn and before the container is removed from the press.